package com.elnguage.lox;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.nio.charset.Charset;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.List;


public class Lox{

    static boolean hadError = false;
    static boolean hadRuntimeError = false;
    static Interpreter interpreter = new Interpreter();
    public static void main(String[] args) throws IOException
    {
        if(args.length > 1)
        {
            System.out.println("Too many args!");
            System.exit(64);
        }    
        else if(args.length == 1)
        {
            runFile(args[0]);
        }
        else
        {
            runPrompt();
        }
    }
    private static void runFile(String path) throws IOException
    {
        byte[] bytes = Files.readAllBytes(Paths.get(path));
        run(new String(bytes, Charset.defaultCharset()));
        if(hadError)
        {
            System.exit(65);
        }
        if(hadRuntimeError)
        {
            System.exit(70);
        }
    }
    private static void runPrompt() throws IOException{
        InputStreamReader input = new InputStreamReader(System.in);
        BufferedReader reader = new BufferedReader(input);
        for(;;)
        {
            System.out.print("> ");
            String line = reader.readLine();
            if(line == null)
                break;
            run(line);
            hadError = false;
        }
    }
    private static void run(String source)
    {
        Scanner scanner = new Scanner(source);
        List<Token> tokens = scanner.scanTokens();

        // for(Token token: tokens)
        // {
        //     System.out.println(token);
        // }

        // System.out.println("-----------------------");

        Parser parser = new Parser(tokens);
        List<BaseStmt> stmts = parser.parse();
        
        if(hadError)
            return;

        interpreter.interpret(stmts);
    }
    public static void error(int line, String message)
    {
        report(line, "", message);
        hadError = true;
    }

    //For parser's error
    public static void error(Token token, String message)
    {
        if(token.type == TokenType.EOF)
        {
            report(token.line, " at '" + token.lexeme + "'", message);
        }
        else
        {
            report(token.line, " at end", message);
        }
    }
    private static void report(int line, String where, String message)
    {
        System.err.println("[line " + line + "] Error" + where + ": " + message);
        hadError = true;
    }

    static void runtimeError(RuntimeError error)
    {
        System.err.println(error.getMessage() + "\n[line " + error.token.line + "]");
        hadRuntimeError = true;
    }
}
